Visual, physical difficulties may increase in patients with late AMD
Adults with late age-related macular degeneration may experience greater visual and physical difficulties compared with adults without AMD, according to study results published in Translational Vision Science and Technology.
“AMD-related central vision loss is associated with difficulty with daily tasks such as reading and driving. As a larger proportion of the U.S. population is living well beyond the age of 60 years and are at risk of developing AMD, an understanding of the impact of AMD on visual and physical functioning in this population is of paramount importance,” William Mitchell, MBBS, MPH, Massachusetts Eye and Ear Infirmary, and colleagues wrote. “To date, the impact of AMD on visual and physical function in a large U.S. cohort representative of the national population has not been described.”
In a cross-sectional study, researchers used the National Health and Nutrition Examination Survey questionnaire to analyze 5,604 adults for the association between AMD and self-reports of functional difficulty. Primary outcomes included item response theory (IRT) scores for visual difficulty and physical difficulty.
Study results yielded 386 participants presenting with early AMD and 55 participants presenting with late AMD. Compared with participants without AMD, participants with late AMD reported higher item visual difficulty (7.1 IRT points [95% CI, 7.0-7.2] vs. 10.1 IRT points [95% CI, 8.2-12.1], respectively; P= .003) and participants with both early and late AMD reported higher item physical difficulty (11 IRT points [95% CI, 10.9-11.1] vs. 11.6 IRT points [95% CI, 11.1-12.1]; P= .005; 13.4 IRT points [95% CI, 11.8-15.0]; P= .03, respectively). Researchers noted lower income, higher medical comorbidities, depression and presenting visual acuity predicted larger visual and physical difficulties among participants with AMD.
“U.S. adults over 40 years of age with late AMD experience substantially greater visual and physical difficulties compared with those without AMD, independent of sociodemographic characteristics and medical comorbidity status,” Mitchell and colleagues concluded. “With an aging U.S. population and the increasing global prevalence of AMD, an awareness of the functional burden of AMD and those particularly at risk, as well as an assessment of visual characteristics other than Snellen presenting [visual acuity] alone, will facilitate a comprehensive approach to the assessment and management of patients with AMD.”
Perspective
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Although AMD is the leading cause of vision loss among older Americans, few high quality, large cohort studies have been done in the U.S. to investigate the potential impacts of AMD on visual and physical function. The recent publication by Mitchell and colleagues suggests that the burden of central vision loss from AMD extends beyond visual acuity and substantially impacts the ability to perform daily physical activities, even in the early stages of the disease.
In the study, even those with mild AMD (drusen and/or pigmentary abnormalities) and good mean acuity of approximately 20/25 had greater reports of physical dysfunction compared with patients without AMD. Likewise, patients with advanced disease features such as geographic atrophy and/or exudation reported substantial visual and physical hardships despite mean acuity levels between 20/40 to 20/50. These findings imply that even patients with what are traditionally considered “functional” acuity measures may have substantial visual and physical function difficulties, and a low threshold for referral for rehabilitation services should be adopted by primary eye care providers. They also highlight the importance of careful screening for functional difficulty particularly with the following types of tasks: reading small print, seeing curbs in dim light, locating items on a crowded shelf, climbing stairs, performing household chores and attending social events. Interestingly, the authors found that self-reported visual difficulty seemed to be independent of Snellen acuity, which suggests that additional visual function testing such as contrast sensitivity and microperimetry may be needed to identify those with functional difficulties worthy of referral.
Individuals with lower income, depression and medical comorbidities — such as stroke, diabetes and heart disease — were more likely to report functional hardship. Therefore, an interprofessional team approach that includes medical management of comorbidities, rehabilitation counseling for depression, low vision rehabilitation, as well as occupational and physical therapies likely represents the ideal care model for AMD patients to optimize quality of life.
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